Hi Messicamouse,
First off - RELAX! Your jaw needs your body to relax in order to heal. Basically, something has caused your meniscus (disc) to get caught up in the jaw bones and cartilage/ligaments. Your muscles are now in spasms which don't allow the area to relax and go back to the position it needs to. You now may have some damage, BUT maybe not! That "something" could be grinding your teeth at night because of added stress or an injury of sorts, etc.
Is your jaw still locked shut?? Since your doctor didn't seem to be able to help you, you are going to have to help yourself. First - do anything and everything you can to relax. Hot tub, hard exercise, massage (good therapeutic MT), etc.
The ice rotated with moist heat is essential for any swelling and/or other damage (directly on the joint(s)). You should be doing this several times a day, especially moist heat around the neck (for relaxation). Eat only soft food or even a liquid diet for a few weeks. Do not open your mouth too wide or too long at any one time, also for a few weeks. NO gum chewing or ice eating or eating anything too hard, big, gooey or chewy. Watch your posture closely, especially in front of the computer screen. Do NOT jut your chin out or up, keep shoulders back, down & relaxed.
Flexerill has never helped me, but Zanaflex has, I just can't do anything when I take it. You might also want to consider Valium or Xanax for a few weeks to take at night when sleeping. Getting good sleep is so important because that's when our body repairs itself, but I also know what it's like to be in pain and "trying" to sleep.
You can't give up. You still have a couple of months before the trip. Your first priority should be to get the jaw unlocked (hopefully without "popping" it). I personally don't think you really need to see an oral surgeon just yet. Surgery should ALWAYS be the last option. You gain a whole list of other problems when you have surgery, and jaw surgery in particular does not have a decent enough success rate, yet. You might want to consider getting a bite splint as soon as possible, tho, and it doesn't have to be a "specialist;" just a dentist who knows how to make and adjust them. That's the type of specialist I see (not very often anymore.)
BUT IF your jaw is still locked - you might even consider going to an emergency room (or a dental school), being medicated and then rather forcibly pop the jaw back into joint. After that, you will have to be very careful not to pop it out again by doing the above self-help treatments, etc.
If you have any questions, please feel free to post or even PM me. RELAX!!!
God bless...
Carol